Manchester United’s players were jeered by their own supporters as they were humiliated by bitter rivals Manchester City in the League Cup.
The first half - as manager Ole Gunnar Solskjaer admitted - was United's worst 45 minutes of the season, and the latest example of the gulf which has opened up between the blue and red halves of Manchester.
In the end, City came away from Old Trafford with a 3-1 victory but knowing it could have been an even bigger scoreline after the one-sided first leg of their semi-final.
“Of course, Manchester United can come back," City manager Pep Guardiola said, looking ahead to the second leg at Etihad Stadium on January 29. "They have the shirt which means history and pride.”
Guardiola will know, however, that this semi-final should be over.
City put on a first-half masterclass, netting three goals from the 19th to the 38th minutes and looking like scoring every time they went forward. Guardiola didn't play a recognised striker, instead flooding his midfield to dominate possession and spring forward in attack.
United couldn't cope and Solksjaer admitted: “We didn't deal with their system well enough.”
When the visitors went 3-0 up courtesy of an own-goal by Andreas Pereira, memories were revived of the 6-1 win on this ground by Roberto Mancini’s City in 2011 that was an early signal of the shifting of the balance of power in Manchester. It was the first time since 1997 that United had conceded three first-half goals in a match at Old Trafford.
However, United managed to avoid conceding any more and a 70th-minute strike by Marcus Rashford gave Solskjaer’s team a glimmer of hope heading into the second leg. Both Solskjaer and Guardiola acknowledged United advancing from the Champions League round of 16 last season after losing 2-0 to Paris Saint-Germain at home in the first leg.
“We've shown before we have been down from a home tie and turned it around,” Solskjaer said. “PSG is the latest example and we have to believe that we can put on a performance.”
City have won the League Cup the last two seasons and are now unbeaten in 16 matches in the competition, dating back to a loss at United in the fourth round in October 2016.
Mindful of how United tore apart his City team on the counter attack in a Premier League game won by Solskjaer’s side at the Etihad last month, Guardiola left out strikers Sergio Aguero and Gabriel Jesus and overloaded the midfield.
“We win and we're a genius,” Guardiola said, "but if we don't win I know what will happen. We try to control the counter attacks because they're a wonderful team."
City’s midfielders picked their moments to charge forward, and did so with devastating effect.
Bernardo Silva was unchallenged as he advanced towards the edge of United’s penalty area and drove a fierce, curling shot into the top corner in the 17th minute.
The Portuguese playmaker then threaded a perfectly weighted through ball to Riyad Mahrez, who ran on to the pass, rounded goalkeeper David de Gea and slotted the ball into an empty net.
United were reeling and it got worse. Again the defence opened up as Kevin De Bruyne went round Phil Jones and fired in a left-footed shot that was saved by De Gea, only for the ball to ricochet off the shin of Pereira and rebound into the net.
With Raheem Sterling wasting two glorious chances, City should have gone into halftime with an even bigger lead.
“You might say we were lucky to be only 3-0 down at half time,” Solskjaer said.
“Football is crazy, anything can happen," City defender Kyle Walker said. “But we're in a good position.”